We have recently observed P31 NMR spectra of dry powders, liposomes, and oriented bilayers of dipalmitoyllecithin using solid state high resolution NMR techniques. The spectra of the powders and liposomes change dramatically with water and cholesterol concentration and spectra of oriented samples show effects of phospholipid orientation, head group motion, and molecular packing. We propose to use three features of solid state NMR spectra-chemical shift, quadrupolar, and dipolar tensors- to further investigate these effects and to examine phospholipid bilayer structure and dynamics. With P31 and H2 NMR we plan to determine head group orientation and with C13 spectra chain orientation as a function of bilayer water content and temperature. Furthermore H2 dipolar broadening in P31 spectra of selectively deuterated and H2O solvated lipids should yield specific information on molecular packing and on the position of water in bilayers. In addition, we will employ these techniques to assess the effects of cholesterol and peptide antibiotics on lipid conformation. Finally, we plan to study HI dipolar splittings in C13 spectra of selectively enriched cholesterol to determine the orientation of this molecule in oriented bilayer samples and H2 spectra of selectively labelled sterol to determine its mobility.